What Virus causes the disease COVID-19?

SARS-CoV-2 is a virus that causes Covid-19. A virus is a genetic material contained within an organic particle that invades living cells and uses its host’s metabolic processes to produce a new generation of viral particles.

How big are viruses?

The size of a single human hair is comparable to the size of as little as 400 SARS-CoV-2 particles to as many as 1,000 particles.

Virus sizes vary from the extremely minuscule – 17 nanometre wide Porcine Circovirus, for example – to monsters that challenge the very definition of ‘virus’, such as the 2.3 micrometer Tupanvirus.

How much smaller are most viruses in comparison to bacteria? Much smaller. With a diameter of 220 nanometers, the measles virus is about 8 times smaller than E.coli bacteria

Are viruses living or not?

For about 100 years, the scientific community has repeatedly changed its collective mind over what viruses are.

First seen as poisons, then as life-forms, then biological chemicals. Viruses today are thought of as being in a gray area between living and nonliving. They cannot replicate on their own, but can do so in truly living cells and can also affect the behavior of their hosts profoundly.

Some say it’s more accurate to think of viruses as part of the continuum between chemistry and biology, one that isn’t clearly divided into living and non-living.


When could we first see viruses?
Electron microscopes were invented in the 1930s. For the first time, we could see what viruses looked like, such as the H1N1 virus that caused the 1918 Spanish flu.

Where did the word virus come from?
The word virus comes from a Latin word describing poisonous liquids. This is because early forms of isolating and imaging microbes couldn’t capture such tiny particles.

Resources, including good Covid short videos

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Five Covid-19 Misconceptions That Are Important To Know

9-25-20 5 common coronavirus misconceptions and the science you need to know– 4-minute video plus a short, well-written article with lots of references for more information Speaker: Dr. Sanjay Gupta CNN Chief Medical Correspondent. To watch the video and read the explanations, click here.

I have written about all of these topics in this blog and previous newsletters . This short video and article put the primary misconceptions in one place. I hear and read about them online a lot. These Five Covid-19 Misconceptions Are Very Important To Know

The 5 Misconceptions

  • Misconception No. 1: Only older people are impacted by the virus
  • Misconception No. 2: Masks don’t protect you against coronavirus
  • Misconception No. 3: You can only catch Covid-19 if you’ve been in close contact with someone who has symptoms
  • Misconception No. 4: This is like the flu
  • Misconception No. 5: Everyone can a get a vaccine this winter


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Dr. Fauci answers questions many people have

Posted on youtube 8/31/20 34 minutes. Tiffany Haddish is an actress and comedian. There was lots of smiling and laughing. She asked about all the stuff on his wall in the the rear. A question I always have ;> Quite a contrast to Fauci’s usually very serious interviews! Dr. Fauci answers questions many people have. I get these questions a lot when people find out I write about Covid.

If you, or someone you know, want understandable explanations from a widely recognized expert for questions that a lot of people have, email the link to them.

The first question was “Was the coronavirus manufactured in a lab or did it come from bats?

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How the death rate is determined in a pandemic

My next-door neighbor died in his sleep awhile ago. The day before he was pruning his fruit trees. He had died in his bed. He was over 75 and had heart problems. We called the police. No investigation. No autopsy. His death was recorded in public records as a heart attack.

But when pandemics are surging, such as in New York and Italy, people die in their homes or on the way to the hospital. Hospitals were overwhelmed. We did not know much then about Covid-19. Sometimes deaths were not recorded as due to Covid-19.

There have been issues in the past about how the cause of death is estimated. For example, suicide, which many families don’t want recorded. Or AIDS, when the epidemic was very strong. In some rural areas, for example, the coroner is not a physician and maybe a funeral director or other occupation. For Covid, people who died tended to have serious pre-existing conditions, which can make selecting one specific cause of death difficult.

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Coronavirus, Novel Coronavirus, SARS-CoV-2, Covid-19 What are the definitions?

The new virus was identified as a coronavirus by Chinese scientists in December 2020. The virus was labeled “novel” because it has never infected humans. It has probably been around for some time in animals, possibly bats. Since December, 2020, the terminology has changed. Coronavirus, Novel Coronavirus, SARS-CoV-2, Covid-19 What are the definitions?

What are coronaviruses?

Coronaviruses are named for the crown-like spikes on their surface. Human coronaviruses were first identified in the mid-1960s. Seven coronaviruses can infect people.

Coronaviruses are a large family of viruses that are common in people and many different species of animals, including camels, cattle, cats, and bats. The total number of coronaviruses is not known. Bats can host thousands of types without getting sick.

Coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. The virus can cause severe acute respiratory syndrome (SARS). Three recent examples of this are SARS-CoV, and MERS-CoV, (Middle Eastern Respiratory Syndrome) and the most recent: SARS-CoV-2

How SARS-CoV-2 was named

This new coronavirus is similar to SARS-CoV. The virus was named SARS-CoV-2 by the International Committee on Taxonomy of Viruses on February 11. It was discovered in 2019.

The disease caused by the virus was named COVID-19 (COronVIrusDisease-2019) by WHO on Feb. 11.

For more information on SARS-CoV, and MERS-CoV see the August 23 post below: Previous epidemics and pandemics https://covidscienceblog.com/previous-virus-epidemics-and-pandemics/

Why what scientists say about COVID keeps changing

SARS-Cov-19, the virus that causes the disease COVID-19, is a new (novel) coronavirus. No human had ever been infected by the virus.

Scientists looked at other recent coronaviruses, such as SARS, MERS, swine flu, and influenza viruses to help them understand COVID-19. Scientists are learning more daily, even hourly.

Scientific research is shared openly and is transparent. For COVID this means new results can change what we understand about it.

Sometimes what was reliable last week may be wrong this week. We will know a lot more in 2 years, 5 years, 10 years, etc. But, recommendations had to be made early in the pandemic, based on the viruses we knew about.

Comparing Covid to seasonal influenza (flu)

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SARS-CoV-19, the virus that causes the disease COVID-19, is a very efficient virus

Viruses are not alive. Their only reason for existing is to reproduce and spread to as many hosts as possible. All viruses mutate. Some mutations are very successful. All viruses mutate, including SARS-CoV-19. UPDATED 2-11-21

Every time a virus copies itself (replicates) it may mutate. When the virus is spreading widely, the mutations increase. This means more opportunities for the virus to become “better” at infecting us. The U.K. virus is spreading widely in the U.S. and may be mutating to become more hazardous to humans. The “original” virus may also be mutating.

Both the UK and South African viruses are in my county in the Bay Area. Almost everyone has been wearing face masks since April. Stanford University is doing the testing here. They are probably spreading rapidly in many other states, but there is limited testing to detect them.

2-11-21 UPDATE Coronavirus Variants – What They Mean Video, 36 minutes. February 11, 2021. An excellent expert speaker (virologist) you can understand, with practical examples. Includes timed topics so you can find what you want to learn more about. 2-8-21 Video 36 minutes.

1-25-21 UPDATE: Virus Mutations (variants)

Preliminary research suggests the United Kingdom Covid mutation (variant) makes the SARS-CoV-2 virus is over 50% transmissible. Per Dr. Fauci, it may cause more deaths. We don’t know where it is spreading in the U.S. due to a lack of genomic surveillance to identify what was causing people to get infected“original” Covid or a variant.

1-18-21 Excellent podcast What You Need to Know About the Variants 49 minutes, but worth the time. The best variant interview I have ever heard. Understandable and very well done. “So-called” UK and South African variants with virologist Angela Rasmussen and evolutionary biologist Paul Turner.

In the United Kingdom, about 10% of the virus samples from infected persons are genetically sequenced. In the U.S., about 0.3% of virus samples are sequenced. Biden plans on increasing this.

This is a new (novel) type of coronavirus. Humans have no immunity. Every human can be infected. We do not yet know if any of us has “natural” immunity (cannot get infected).

The virus kills a relatively low percentage of people (estimated around 1%), compared with Ebola at 50%. About 6.5% died in the 1908 Spanish flu.

With Covid, more people are left alive to infect. It is easily transmitted through the air (respiratory), much more efficient than requiring close physical contact (Ebola), and mostly kills old people, especially over 80. More younger humans are left alive to infect.

About 50% (estimate has varied over time) of people infected with the virus have no symptoms (asymptomatic) and can spread the virus. This is unusual for a virus and greatly increases its ability to expand into many humans.

Emerging research suggests that people may actually be most contagious during the 48 hours before they start to experience symptoms. It can take between 1-14 days for COVID symptoms to show up. More time for infected people to spread the virus and infect others.

It “waits” for humans to help it expand by leaving their homes, not using face masks or doing physical distancing, crowding inside rooms with lots of unmasked people and poor ventilation, not washing hands, etc.

If you are infected no one knows if you will be immune or for how long. Some viruses, such as in the seasonal flu, regularly mutate, so humans have relativity short immunity time.

On the plus side, it is a “starter” virus, much less deadly than SARS, with a 10% death rate or Ebola at 40%. It is less contagious than measles, which has very tiny droplets, that can remain suspended in the air for up to two hours after someone with measles has left an area.